ES2916836T3 - Mineral fiber mats comprising a binder based on lignosulfonate and a carbonyl compound - Google Patents

Abstract

The invention relates to an aqueous binder for mineral fibers, in particular glass fibers, said binder comprising: at least one ammonium lignosulfonate or an alkali metal or alkaline earth metal salt of lignosulfonic acid; and at least one carbonyl compound of the formula R-[c(O)R1]x(i), in which: R represents a linear, branched or cyclic, saturated or unsaturated hydrocarbon radical, a radical containing one or more aromatic nuclei of 5 or 6 carbon atoms, a radical containing one or more aromatic heterocycles containing 4 or 5 carbon atoms and an oxygen, nitrogen or sulfur atom, for which Radical R may contain other functional groups, such as hydroxyl or alkoxy, in particular methoxy; - R1 represents a hydrogen atom or a C1-C10 alkyl radical; and - X varies between 1 and 10, said that the folder is free of hydrogenated sugar and melamine. The invention also relates to fibrous products that take the form of mineral fiber mats. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Mineral fiber mats comprising a binder based on lignosulfonate and a carbonyl compound

The present invention relates to the field of products comprising mineral fibres, in particular glass fibres, bound by means of an organic binder without formaldehyde.

The present disclosure relates more particularly to an aqueous thermally crosslinkable binder including at least one lignosulfonate and at least one carbonyl compound, and also to the mineral fiber based products resulting therefrom.

The mineral fiber-based products to which the invention refers more particularly are mats of mineral fibers, in particular glass fibers, (also known as "non-woven fabrics" or "veils") that are manufactured according to known procedures that come from the dry route or the wet route.

In the dry route process, the molten material present in a furnace is transported to a set of nozzles from which filaments flow by gravity and are dragged by a gaseous fluid. Continuous mineral strands are collected on a conveyor, where they intertwine, forming a mat.

A binder is applied to the top face of the mat thus formed using an appropriate device, generally proceeding by curtain coating, and excess binder is removed by suction on the opposite face. Subsequently, the mat enters a device containing hot air, whose temperature, in the order of 200 to 250 °C, is adjusted to remove the water and cross-link the binder in a very short time, in the order of approximately ten seconds to 1 minute. , and then the mineral fiber mat is collected in the form of a roll.

In the wet method, the mat is obtained from an aqueous dispersion of cut mineral fibers that is deposited, by means of a shaping head, on a conveyor equipped with perforations and the water is extracted through the conveyor by virtue of of a suction chamber. The cut mineral fibers that remain on the conveyor form a mat that is treated under the same conditions as those described for the dry process.

In the processes mentioned above, the role of the binder is to bind the mineral fibers together and to confer, on the mat containing them, mechanical properties suitable for the intended use, in particular sufficient rigidity to allow it to be easily handled without the risk of can tear apart.

The binder to be applied to the mineral fibers is generally in the form of an aqueous solution containing at least one thermosetting resin and additives, such as a catalyst for crosslinking the resin, a silane adhesion promoter, a hydrophobic substance, etc.

The most widely used thermosetting resins are formaldehyde-based resins, in particular phenolic resins belonging to the resole family, urea-formaldehyde resins and melamine-formaldehyde resins. These resins have good crosslinking capacity under the thermal conditions mentioned above, are soluble in water, have a good affinity for mineral fibers and are also relatively inexpensive.

However, these resins are likely to contain free formaldehyde, the presence of which is undesirable due to undesirable effects on human health and the environment. For some years, regulations regarding environmental protection have become more restrictive and force manufacturers of resin and fibrous products to look for solutions that make it possible to further reduce the content of free formaldehyde.

Solutions to replace formaldehyde-based resins for bonding mineral fibers are known and are based on the use of a carboxylic acid polymer in combination with a p-hydroxyamide and an at least trifunctional monomeric carboxylic acid (US-5 340868).

Adhesive compositions comprising an alkanolamine containing at least two hydroxyl groups and a polycarboxylic polymer have been proposed (US-6 071 994, US-6 099773, US-6 146746, US-2002/091185).

Adhesive compositions comprising a polycarboxylic polymer, a polyol and a catalyst have also been described, phosphorus-containing catalyst (US-5 318 990, ^or S-5661 213, US-6 331 350, US-2003/0008978), a fluoroborate (US-5977232) or a cyanamide, a dicyanamide or a cyanoguanidine (US-5 932689).

Furthermore, adhesive compositions based on saccharides capable of cross-linking under the effect of heat are known.

In US-5 895 804, the adhesive composition comprises a polycarboxylic polymer having at least two carboxylic acid functional groups and a molecular weight of at least 1,000, and a polysaccharide having a molecular weight of at least 10,000.

CN 103 031 108 A describes a method for manufacturing an adhesive composition comprising glyoxal and alkali metal lignosulfonate, in the form of an aqueous solution. FR 2208 963 A1 describes an aqueous adhesive composition comprising alkali metal or alkaline earth metal lignosulfates and furfural.

US-2014/113123 A1 describes an aqueous binder composition for mineral fiber mats, comprising a lignosulfate and thermosetting phenol-formaldehyde resin.

Finally, WO 2012/172252 describes a formaldehyde-free aqueous binder for fiber mats comprising (in parts by weight): a salt of lignosulfonic acid (from 20 to 95 parts), an oligosaccharide (from 5 to 80 parts) and a catalyst of cross-linking selected from compounds containing phosphorus and sulfates (from 5 to 20 parts per 100 parts of lignosulfonic acid salt and oligosaccharides).

The present invention relates more particularly to fibrous products based on mineral fibres, in particular glass fibres, which are in the form of mats, according to claim 1.

In particular, the target mats are intended for the manufacture of waterproof bituminous roofing membranes. The purpose of this description is to propose an alternative to binders likely to contain or generate formaldehyde and which make it possible to confer good mechanical properties on mats based on mineral fibres, in particular an improved breaking strength.

This object is achieved by virtue of the aqueous binder for mineral fibres, in particular glass fibres, comprising - at least one ammonium lignosulphonate or an alkali metal or alkaline earth metal salt of lignosulphonic acid, and - at least one carbonyl compound of formula

R-[C(O)R1]x (I)

in which:

- R represents a saturated or unsaturated and linear, branched or cyclic hydrocarbon radical, a radical containing one or more aromatic rings consisting of 5 or 6 carbon atoms, a radical containing one or more aromatic heterocycles containing 4 or 5 carbon atoms and an oxygen, nitrogen or sulfur atom, it being possible for the radical R to contain other functional groups, especially hydroxyl or alkoxyl groups, in particular methoxyl groups,

- R1 represents a hydrogen atom or a C1-C10 alkyl radical, et

- x varies from 1 to 10,

said binder being devoid of hydrogenated sugar and melamine.

Ammonium lignosulfonate is a by-product resulting from the treatment of wood for the manufacture of paper pulp according to the "sulfite" process. The treatment of paper pulp with ammonium sulphite or ammonium bisulphite allows to obtain ammonium lignosulphonates.

In addition, ammonium lignosulfonate makes it possible to confer fire-resistance properties on the binder.

The alkali or alkaline earth metal salts of sulfonic acid are generally complex mixtures of various lignosulfonic acids in salified form, commonly referred to as "lignosulfonates". Lignosulfates are by-products resulting from the treatment of wood for the manufacture of paper pulp according to the "sulfite" process mentioned above that uses a sulfite or a bisulfite. Depending on the nature of the sulfite or bisulfite counterion used, in particular alkali metal or alkaline earth metal salts of lignosulfonic acid are obtained. In the present invention, the preferred alkali metal salts of lignosulfonic acid are sodium or potassium lignosulfates, advantageously sodium, and the preferred alkaline earth metal salts of lignosulfonic acid are magnesium or calcium lignosulfonates.

The carbonyl compound is a monofunctional or polyfunctional aldehyde selected from the group consisting of acetaldehyde, propionaldehyde, dimethoxyethanal, butyraldehyde, in particular n-butyraldehyde, glyoxal, malonaldehyde, succinaldehyde, glutaraldehyde, 2-hydroxyglutaraldehyde, 3-methylglutaraldehyde, adipaldehyde, suberaldehyde, sebacalaldehyde, malealdehyde, fumaraldehyde, poly(acroleins), dialdehyde starch, furfural (2-furancarboxaldehyde), 5-methylfurfural (2-methyl-5-furancarboxaldehyde), hydroxymethylfurfural (2-hydroxymethyl-5-furancarboxaldehyde), 2,5- Furancarboxydialdehyde, vanillin and vanillin polymers, in particular bis-vanillin, cinnamaldehyde and polymers of cinnamaldehyde, phthalaldehyde, isophthalaldehyde, terephthalaldehyde and the oligomers of the following formulas (III) and (IV):

( ^{i i i} )

( ⁱⁱⁱ )

in which:

A represents a divalent radical -CH2-, -CH(OH)- or -CH2-O-CH2-, n varies from 1 to 8,

where n' varies from 1 to 9.

Hydroxymethylfurfural is particularly preferred.

In the binder, the ammonium lignosulfonate or the alkali metal or alkaline earth metal salt of lignosulfonic acid generally represents 30 to 95% by weight of the mixture consisting of the ammonium lignosulfonate or the alkali metal or alkaline earth metal salt of lignosulfonic acid. lignosulfonic acid and the carbonyl compound of formula (I), preferably from 40 to 80% and advantageously from 50 to 70%.

The binder may further comprise:

- at least one homopolymer of vinyl acetate or a copolymer of vinyl acetate and at least one hydrophobic monomer such as ethylene, propylene, butylene, styrene or vinyl chloride, preferably ethylene. The aforementioned homopolymer and copolymer are generally present in an amount equal to at most 15 parts by weight per 100 parts by weight of ammonium lignosulfonate or alkali metal or alkaline earth metal salt of lignosulfonic acid and carbonyl compound of formula (I ), Y

- at least one polysaccharide, for example a starch. The polysaccharide is generally present in an amount equal to at most 50 parts by weight per 100 parts by weight of ammonium lignosulfonate or alkali metal or alkaline earth metal salt of lignosulfonic acid and of the carbonyl compound (I).

When the binder contains ammonium lignosulfonate, it may further contain at least one compound selected from phosphorus-containing compounds and ammonium sulfate.

Mention may be made, by way of examples of phosphorous-containing compounds, of alkali metal hypophosphite salts, alkali metal phosphites, alkali metal polyphosphates, alkali metal hydrogen phosphates, phosphoric acids and alkylphosphonic acids, wherein the alkali metal is preferably sodium or potassium, and ammonium phosphates, in particular diammonium phosphate. The content of the aforementioned compound is at most equal to 20 parts by weight per 100 parts by weight of ammonium lignosulfonate and carbonyl compound of formula (I).

The binder according to the invention may also comprise the following conventional additives in the following proportions, calculated on the basis of 100 parts by weight of ammonium lignosulfonate or alkali metal or alkaline earth metal salt of lignosulfonic acid and carbonyl compound of formula (YO):

- from 0 to 1 part by weight of silane, preferably from 0.1 to 0.5 part,

- 0 to 5 parts by weight of a silicone, vegetable oil or fluorinated compound, preferably 0.1 to 1 part, and

- from 0 to 5 parts of a plasticizing agent, in particular glycerol.

The role of the additives is known and is briefly discussed: the silane is an agent for the coupling between the fibers and the binder, and also acts as an antiaging agent; silicone, vegetable oil and fluorinated compound are hydrophobic substances, whose role is to reduce the absorption of water by the mineral fiber mat. The binder is provided in the form of an aqueous solution.

When the binder contains ammonium lignosulfonate, the preferred silane is an aminosilane.

The binder containing an alkali metal or alkaline earth metal salt of lignosulfonic acid is devoid of nitrogenous compounds, which is advantageous since for this reason the gaseous emissions generated during the heat treatment aimed at crosslinking the binder do not contain nitrogen. The treatment of waste products at the furnace outlet in industrial plants is therefore easier to carry out. The binder is especially intended to be applied to mineral fibers consisting of glass or a rock, in particular basalt, and preferably glass, to form a mat.

Conventionally, the binder is deposited on a mat of mineral fibers (formed by the dry or wet route) and then the mat is treated at a temperature that allows the binder to crosslink, which then becomes infusible. The crosslinking of the binder is generally carried out under conditions comparable to those of a conventional formaldehyde-containing resin, generally at a temperature ranging from 200 to 220 °C and for a very short period of time, in the order of a few seconds to 1 minute.

Mineral fibers are both mineral filaments and yarns composed of a multitude of mineral filaments linked together, in particular by size, and sets of such yarns. The mineral filaments and threads can be continuous or discontinuous.

Therefore, according to a first embodiment, the mat of mineral fibers is made up of discontinuous mineral filaments with a length that can reach 150 mm, preferably varying from 20 to 100 mm and advantageously from 50 to 70 mm, and having a diameter which can vary within wide limits, for example from 5 to 30 pm. According to a second embodiment, the mineral fiber mat is composed of mineral yarns.

Mineral yarns can be yarns composed of a multitude of mineral filaments (or base yarns) or sets of these base yarns in the form of rovings.

The aforementioned yarns may be zero twist yarns or twist yarns (or textile yarns), preferably zero twist yarns.

Mineral threads, in particular glass threads, are generally cut to a length that can range up to 100 mm, preferably varying from 6 to 30 mm, advantageously from 8 to 20 mm and better still from 10 to 18 mm.

The diameter of the glass filaments constituting the yarns can vary within wide limits, for example from 5 to 30 pm. In the same way, wide variations in the linear density of the yarn can occur, which can range from 34 to 1500 tex.

The glass involved in the formation of the filaments can be of any type, for example C, E, R or AR (alkali resistant). E or C glass is preferred.

Although the invention relates more particularly to mats consisting of mineral fibres, in particular glass or rock fibres, as already mentioned, it cannot be ruled out that the mat contains a small proportion of organic fibres, for example, which represents as maximum 20% of the weight of the mineral fibres. The organic fibers can be synthetic fibers or natural fibers.

As examples of synthetic fibers, fibers consisting of a polyolefin, for example, of polyethylene or polypropylene, of a poly(alkylene terephthalate), for example, polyethylene terephthalate, or of a polyester, may be mentioned. There may be mentioned, as examples of natural fibres, vegetable fibres, eg cotton, coconut, sisal, hemp or flax fibres, and animal fibres, eg silk or wool.

The mineral fiber mat may be reinforced, if appropriate, by continuous fibers which are deposited generally on the mat conveying device in the direction of mat travel and are distributed over all or part of the width of the mat. These fibers are generally deposited in the thickness of the mat, prior to the application of the binder.

The reinforcing fibers can be mineral and/or organic fibers of the same chemical nature as the aforementioned fibers involved in the formation of the fiber mat according to the invention.

Reinforcing fibers made of glass are preferred.

The mineral fiber mat generally has a weight per unit area ranging from 10 to 1100 g/m2, preferably from 30 to 350 g/m2 and advantageously from 35 to 75 g/m2.

The binder generally represents from 5 to 40% by weight of the mineral fiber mat, preferably from 10 to 30%.

The mineral fiber mat according to the present invention is especially intended for the production of airtight bituminous membranes. However, the mineral fiber mat can also be used in other applications, for example, as wall and/or ceiling coverings (to be painted or not), surface covering or sealing for drywall or cement board, covering surface for thermal and/or acoustic insulation products, such as mineral wool or a foam intended more particularly for roof insulation, or to produce a floor covering, in particular an acoustic underlay.

The following examples make it possible to illustrate the invention without limiting it.

In these examples, the breaking stress of a 5 cm x 25 cm sample attached at one end to a tensile testing machine and subjected to a continuous elongation of 40 mm/minute is measured. The breaking stress is expressed in N/5 cm. Tensile strength is measured after (initial) fabrication and after the sample has been treated under the following conditions (a) accelerated aging in a heated chamber at 50°C under 98% relative humidity for 3 days, (b) treatment in water at 80 °C for 10 minutes. The result is expressed by the percent retention, which is equal to: (breaking stress after treatment/initial breaking stress) x 100. Examples 1 to 6

Aqueous binders are prepared comprising the constituents listed in Table 1 in proportions expressed as parts by weight of solids. The reference binder (indicated as Ref.) is representative of the state of the art described in WO 2012/172252.

The binders are prepared by introducing the different constituents into a container containing water at room temperature, with moderate agitation.

The solids content (dry matter) of the binders is equal to 20%.

Use is made of a mat of E-glass filaments having a diameter of 13 pm and a length of 18 mm. The weight per unit area of the mat is equal to 75 g/m2.

The mat is immersed in the binder for 30 seconds and then the excess is removed by suction. The mat is post-treated in an oven at 210°C for 60 seconds. Ultimately, the mat contains 20% by weight of binder.

The properties of each mat are given in Table 1.

Examples 1 to 3 have an initial breaking stress and a breaking stress after accelerated aging that are improved over the Reference.

In addition, Examples 2, 3 and 6, after treatment with water, have a better breaking strength with respect to the Reference.

Table 1

Claims (13)

Yo. A mat comprising mineral fibers, characterized in that the fibers are bound by an aqueous binder comprising - at least one ammonium lignosulfonate or an alkali metal or alkaline earth metal salt of lignosulfonic acid, and - at least one carbonyl compound selected from the group consisting of acetaldehyde, propionaldehyde, dimethoxyethanal, butyraldehyde, in particular n-butyraldehyde, glyoxal, malonaldehyde, succinaldehyde, glutaraldehyde, 2-hydroxyglutaraldehyde, 3-methylglutaraldehyde, adipaldehyde, suberaldehyde, sebacalaldehyde, malealdehyde , fumaraldehyde, poly(acroleins), dialdehyde starch, furfural (2-furancarboxaldehyde), 5-methylfurfural (2-methyl-5-furancarboxaldehyde), hydroxymethylfurfural (2-hydroxymethyl-5-furancarboxaldehyde), 2,5-furancarboxydialdehyde, vanillin and vanillin polymers, in particular bis-vanillin, cinnamaldehyde and polymers of cinnamaldehyde, phthalaldehyde, isophthalaldehyde, terephthalaldehyde and the oligomers of the following formulas (III) and (IV):

where: A represents a divalent radical -CH2-, -CH(OH)- or -CH2-O-CH2-, n varies from 1 to 8,

where n' varies from 1 to 9, said binder being devoid of hydrogenated sugar and melamine. 2. The mat according to claim 1, characterized in that the ammonium lignosulfonate or the alkali metal or alkaline earth metal salt of lignosulfonic acid represents from 30 to 95% of the weight of the mixture consisting of the ammonium lignosulfonate or the salt of alkali metal or alkaline earth metal of lignosulfonic acid and the carbonyl compound of formula (I), preferably from 40 to 80% and advantageously from 50 to 70%. 3. The mat according to claim 1 or 2, characterized in that it further comprises: - at least one homopolymer of vinyl acetate or a copolymer of vinyl acetate and at least one hydrophobic monomer, and - at least one polysaccharide. 4. The mat according to claim 3, characterized in that the homopolymer or copolymer of vinyl acetate and at least one hydrophobic monomer is present in an amount equal to at most 15 parts by weight per 100 parts by weight of ammonium lignosulfonate or of alkali metal or alkaline earth metal salt of lignosulfonic acid and of carbonyl compound of formula (I). 5. The mat according to claim 3, characterized in that the polysaccharide is present in an amount equal to at most 50 parts by weight per 100 parts by weight of ammonium lignosulfonate or alkali metal or alkaline earth metal salt of lignosulfonic acid and of carbonyl compound of formula (I). The mat according to one of claims 1 to 5, characterized in that it contains an ammonium lignosulfonate and at least one compound selected from phosphorus-containing compounds and ammonium sulfate. 7. The mat according to claim 6, characterized in that the phosphorous-containing compound and ammonium sulfate are present in an amount equal to at most 20 parts by weight per 100 parts by weight of ammonium lignosulfonate and ammonium carbonyl compound. formula (I). 8. The mat according to one of claims 1 to 7, characterized in that it further comprises the following conventional additives in the following proportions, calculated on the basis of 100 parts by weight of ammonium lignosulfonate or alkali metal or alkaline earth metal salt of lignosulfonic acid and of the carbonyl compound of formula (I): - from 0 to 1 part by weight of silane, preferably from 0.1 to 0.5 part, - 0 to 5 parts by weight of a silicone, vegetable oil or fluorinated compound, preferably 0.1 to 1 part, and - from 0 to 5 parts of a plasticizing agent, in particular glycerol. The mat according to one of claims 1 to 8, characterized in that it contains an alkali metal or alkaline earth metal salt of lignosulfonic acid and is devoid of nitrogenous compounds. The mat according to one of claims 1 to 9, comprising rock or glass mineral fibres. 11. The mat according to one of claims 1 to 10, characterized in that it has a weight per unit area ranging from 10 to 1100 g/m2, preferably from 30 to 350 g/m2 and advantageously from 35 to 75 g. /m2. 12. The mat according to one of claims 1 to 11, characterized in that the binder represents 5 to 40% by weight of said mat, preferably 10 to 30%. 13. The mat according to one of claims 1 to 12, characterized in that it contains organic fibers in a proportion equal to at most 20% of the weight of the mineral fibres.